Aiming at the problem of moist and thermal coupling effect of winter aqueduct, the finite element model of temperature field, humidity field and humid heat coupling field of concrete box aqueduct with different environmental parameters is established by using Fluent finite element software. Taking an aqueduct in Northwest China as an example, the ambient temperature, ambient humidity and wind speed from January 5 to January 20, 2023 were measured, and the influence of different working conditions on the temperature effects of the aqueduct in the uncoupled and fully coupled state in winter was analyzed. The analysis results show that The most unfavorable temperature difference in winter when the aqueduct is open to water is -14.7 °C and -6.3 °C when it is not water; the most unfavorable transverse temperature difference in winter when the aqueduct is open to water is -10.2 °C and -6.2 °C when no water is not connected; in the process of humidity diffusion, the humidity in the direction of plate thickness gradually decreases from inside to outside, and the water absorption rate decreases with the increase of time; in the process of moist and thermal coupling, the temperature value of the fully coupled field is less than the temperature value of the non-coupling field, the deflection change value of the fully coupling action of humidity and heat is less than the deflection change value under the non-coupling of humidity and heat, and the tensile stress of the moist and thermal coupling action is less than the tensile stress value under the non-coupling of moist heat, therefore, the full coupling of humidity and heat is beneficial to the deformation of the aqueduct structure.